For a home recording space, choose a quiet room with minimal echo. Use soft furnishings to absorb sound and a directional microphone for better audio quality. If you don't have a microphone, place the smartphone close to your mouth and speak clearly to achieve the best possible recording.
Consider this advice before making a recording:https://www.wikihow.com/Record-Audio-on-a-Mobile-Phone
If you have an external microphone, we trust you to use it based on your experience.
If recording audio is new for you, allow yourself several days to practice before recording commercial audio. This also applies to the equipment you might want to buy. Starting with a cheap USB microphone seems more reasonable than before investing in an expensive XLR mic and external audio drive.